Ionospheric response modeling under eclipse conditions: Evaluation of 14 December 2020, total solar eclipse prediction over the South American sector

In this work, we evaluate the SUPIM-INPE model prediction of the 14 December 2020, total solar eclipse over the South American continent. We compare the predictions with data from multiple instruments for monitoring the ionosphere and with different obscuration percentages (i.e., Jicamarca, 12.0°S, 76.8°W, 17%; Tucumán 26.9°S, 65.4° W, 49%; Chillán 36.6°S, 72.0°W; and Bahía Blanca, 38.7°S, 62.3°W, reach 95% obscuration) due to the eclipse. The analysis is done under total eclipse conditions and non-total eclipse conditions. Results obtained suggest that the model was able to reproduce with high accuracy both the daily variation and the eclipse impacts of E and F1 layers in the majority of the stations evaluated (except in Jicamarca station). The comparison at the F2 layer indicates small differences (<7.8%) between the predictions and observations at all stations during the eclipse periods. Additionally, statistical metrics reinforce the conclusion of a good performance of the model. Predicted and calibrated Total Electron Content (TEC, using 3 different techniques) are also compared. Results show that, although none of the selected TEC calibration methods have a good agreement with the SUPIM-INPE prediction, they exhibit similar trends in most of the cases. We also analyze data from the Jicamarca Incoherent Scatter Radar (ISR), and Swarm-A and GOLD missions. The electron temperature changes observed in ISR and Swarm-A are underestimated by the prediction. Also, important changes in the O/N2 ratio due to the eclipse, have been observed with GOLD mission data. Thus, future versions of the SUPIM-INPE model for eclipse conditions should consider effects on thermospheric winds and changes in composition, specifically in the O/N2 ratio

Variations of total electron content during a magnetic storm

En este trabajo se analizan las variaciones del Contenido Electrónico Total (CET) durante una tormenta geomagnética, calculado a partir de mediciones del retardo ionosférico sobre las señales de código y fase, transmitidas por los satélites del Sistema de Posicionamiento Global (SPG). Los datos procesados corresponden a la estación SPG perteneciente al proyecto CAP (Central Andes Project), situada en San Miguel de Tucumán (26° 53’ S , 65° 13’ W), Argentina. Las variaciones del CET ocurridas en los días de abril de 1997 presentan valores altos, comparados con valores promedios del mes de abril calculados con mediciones de nuestro banco de datos de años anteriores. El fenómeno se registró con mayor intensidad en el período comprendido entre los días 9 al 12 de abril de 1997, tomando un valor de Kp=7- (Figure 2) para el día 11. Además se comparó dichos valores con los obtenidos para días anteriores y posteriores a la tormenta. Los valores de CET alcanzados durante la tormenta exceden en un 30 % a los valores que se alcanzan para días calmos durante esa época del año, lo cual provoca mayores errores en el cálculo del posicionamiento mediante el sistema SPG. doi: https://doi.org/10.22201/igeof.00167169p.2002.41.1.26

Longitudinal variations of ionospheric parameters near totality during the eclipse of December 14, 2020

On December 14, 2020, a total solar eclipse occurred whose shadow cone projected over part of South America. Its effect on critical ionospheric frequencies variability is analysed, considering two stations with similar geographical latitudes and a 95% obscuration percentage: Chillán (36.6°S, 72.0°W), in Chile, and Bahía Blanca (38.9°S, 62.2°W), in Argentina. A comparison of the ionospheric response to the eclipse is made with quiet time daily values and the IRI-2016 model. Results indicate that the greatest eclipse impacts are obtained in foE and foF1, with ∼31% and ∼40% of maximum reductions, respectively. Alternatively, weak disturbances are observed in the foF2 case (<20%). The recombination coefficients were calculated for the E- layer and F1-layer with values of α ∼10−9 cm3 s−1 and for F2-layer with values in β ∼10−4 s−1, similar to previous studies. Longitudinal differences between both ionospheric stations are very small for the F1-layer (∼11%), but a much larger variability is found at F2-layer critical frequencies (∼20%). These results suggest different plasma diffusion processes at high altitudes in the different locations that require further investigation in future studies.Fil: de Haro Barbás, Blas Federico. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física; ArgentinaFil: Bravo Sepulveda, Manuel Alejandro. Universidad de Concepción; ChileFil: Elias, Ana Georgina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología; ArgentinaFil: Martínez Ledesma, Miguel. Universidad de Concepción; Chile. Centro Interuniversitario de Física de la Alta Atmósfera; ChileFil: Molina, Maria Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología; ArgentinaFil: Urra, B.. Centro Interuniversitario de Física de la Alta Atmósfera; ChileFil: Venchiarutti, José Valentín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física; ArgentinaFil: Villalobos, C.. Centro Interuniversitario de Física de la Alta Atmósfera; Chile. Universidad Adventista de Chile; ChileFil: Namour, Jorge Habib. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física; ArgentinaFil: Ovalle, Elías M.. Centro Interuniversitario de Física de la Alta Atmósfera; Chile. Universidad de Concepción; ChileFil: Guillermo, Eduardo Daniel. Universidad Tecnológica Nacional. Facultad Regional Bahía Blanca; ArgentinaFil: Carrasco, E.. Universidad de Concepción; ChileFil: de Pasquale, Lorenzo. Universidad Tecnológica Nacional. Facultad Regional Bahía Blanca; ArgentinaFil: Rojo, E.. Centro Interuniversitario de Física de la Alta Atmósfera; Chile. Universidad Adventista de Chile; ChileFil: Leiva, R.. Centro Interuniversitario de Física de la Alta Atmósfera; Chile. Universidad Adventista de Chile; Chil

DataSheet1_Ionospheric response modeling under eclipse conditions: Evaluation of 14 December 2020, total solar eclipse prediction over the South American sector.pdf

In this work, we evaluate the SUPIM-INPE model prediction of the 14 December 2020, total solar eclipse over the South American continent. We compare the predictions with data from multiple instruments for monitoring the ionosphere and with different obscuration percentages (i.e., Jicamarca, 12.0°S, 76.8°W, 17%; Tucumán 26.9°S, 65.4° W, 49%; Chillán 36.6°S, 72.0°W; and Bahía Blanca, 38.7°S, 62.3°W, reach 95% obscuration) due to the eclipse. The analysis is done under total eclipse conditions and non-total eclipse conditions. Results obtained suggest that the model was able to reproduce with high accuracy both the daily variation and the eclipse impacts of E and F1 layers in the majority of the stations evaluated (except in Jicamarca station). The comparison at the F2 layer indicates small differences (<7.8%) between the predictions and observations at all stations during the eclipse periods. Additionally, statistical metrics reinforce the conclusion of a good performance of the model. Predicted and calibrated Total Electron Content (TEC, using 3 different techniques) are also compared. Results show that, although none of the selected TEC calibration methods have a good agreement with the SUPIM-INPE prediction, they exhibit similar trends in most of the cases. We also analyze data from the Jicamarca Incoherent Scatter Radar (ISR), and Swarm-A and GOLD missions. The electron temperature changes observed in ISR and Swarm-A are underestimated by the prediction. Also, important changes in the O/N2 ratio due to the eclipse, have been observed with GOLD mission data. Thus, future versions of the SUPIM-INPE model for eclipse conditions should consider effects on thermospheric winds and changes in composition, specifically in the O/N2 ratio.</p